There is a game system including plural game devices in which plural players are enabled to play a game by operating plural characters that are set in a virtual space. In such a system, all determinations based on the moves of characters are performed in a particular device (server) separate from the game devices, and an image to be displayed at each game device is updated only when information is received from the particular device, as described in Japanese Patent Application Laid-Open Publication No. 2003-047774 (hereinafter referred to as “JP 2003-047774”).
However, in the system disclosed in JP 2003-047774, information (hereinafter referred to as a “game information set”) relating to all the operations performed at each game device (i.e., moves of characters) is reflected to a display of each game device after game information sets are gathered and used for various determinations in the particular device. Therefore, a response time from the time a player operated a player character (the player's own character) until an image corresponding to the operation is displayed at a game device of the player is prolonged due to communication delay. Such a game system is not suited for the execution of a game requiring an extremely short response time such as a shooting game in which plural players operate player characters to cause the characters to move and shoot one another. The same generally applies to a center-terminal type game system and to a master-slave type game system.
The response time can be shortened if a system is configured in a way in which game devices, without involving a particular device, directly communicate with one another on an equal basis (i.e., not in a master-slave relationship) to play the game. There are various types of such systems. For example, it may be configured so that, in each game device, a displayed image is updated in response to the operation by the player without receiving a game information set from a particular device. However, in any variation, each game device associated with the execution of the same game cannot avoid communicating individually with all of the remaining game devices, and therefore, the process is more burdensome than the system as disclosed in JP 2003-047774 in which game devices should only communicate with a particular device. This drawback is even more serious in a case in which a large number of game devices participate in the execution of the same game.
Furthermore, communication delays between game devices are usually not the same, and as a result, contradictions in the game progress are likely to arise. For example, in a system in which a game is executed among the first to the fourth game devices, we assume that the first event takes place at the first game device, and the second event takes place at the second game device. Since a time (communication delay time) required for reporting to another device of an event that has happened in one game device depends on the destination game device, a situation may arise in which the third game device learns of the first event and then of the second event, but the fourth game device learns of the first event after learning of the second event. Because a game usually progresses in the order of the events reported at each game device, contradictions are likely to arise in the progress of the game in a case in which the order of events received varies among different game devices.